The disclosure relates to gas turbine engines. More particularly, the disclosure relates to acoustic panels.
An exemplary acoustic panel, generally referred to as a panel, is shown in U.S. Pat. No. 5,151,311, issued Sep. 29, 1992. Such a panel comprises a honeycomb core. A backing sheet is secured to one face of the core. A foraminate (e.g., perforated) face sheet is secured along the opposite face. A wire mesh is secured along the outer face of the face sheet. Various metallic and non-metallic materials have been used for the core and sheets. Similarly, a variety of adhesives are used for securing the sheets to the core and the mesh to the face sheet.
Failure of the adhesive securing the mesh to the face sheet is one failure mode. The amount and nature of the adhesive initially used in panel assembly is limited by the desire to not excessively block the mesh openings. Exemplary failure involves delamination over an area. Delamination may be accompanied by a rupture (e.g., a simple tear or a loss of some area of material) or not.
Delamination risks further loss of mesh. To prevent such further loss one may need to replace the affected panel, taking an aircraft out of service. One may alternatively resecure the delaminated material. Adhesive resecuring raises issues of occluding the mesh openings. It also may require that the engine/aircraft be taken out of service for sufficient time to cure or be taken to a climate controlled hangar to facilitate cure of the adhesive.